portable electronic apparatuses, such as smartphones, portable phones, tablet computers and wearable devices, have become widespread. Recently, nonportable communication devices capable of communicating with portable electronic apparatuses in the following manner have become widely used. The nonportable communication devices relay communication with a portable electronic apparatus by sound acquisition with a microphone and sound output from a speaker while the portable electronic apparatus is placed at an arbitrary position. Nonportable communication devices may be called handsfree communication devices (Internet-on-Things [IoT] devices).
When a call (sound communication) received in a mobile phone is reproduced by the speaker of a handsfree communication device (nonportable communication device), and further when a person other than the owner of the portable phone is present around the owner, the calling party or owner needs to care about the conversational content. The calling party may need to ask the intended person (owner) to move to a place to leave him/her alone depending on the conversational content. Thus, nonportable communication devices are required to specify whether or not other people are present around the intended person.